The invention concerns aqueous copper etching solutions, containing customary acid etching means based upon iron chloride, copper chloride or peroxide compounds, improved by an addition of halogen compounds, as well as a process for the etching of copper on conductor plates (i.e. printed circuits) and contacted circuits.
It is known to employ acid etching media for the etching of copper during the manufacture of conductor plates.
A disadvantage of the known techniques, particularly with conductor plates having one or more metal cores, such as for example, iron-nickel or iron-cobalt cores, is that on account of the electro-negative character of the employed metal, there arises a cementation of copper, which leads to insufficient adhesion of the copper subsequently chemically deposited for the purpose of making the contacts.
In addition, the metal cores etched according to the known techniques display the disadvantage of a strong back etching (re-etching).